The Collaborative International Dictionary of English v.0.48:
Thick \Thick\ (th[i^]k), a. [Compar. Thicker (-[~e]r); superl.
Thickest.] [OE. thicke, AS. [thorn]icce; akin to D. dik,
OS. thikki, OHG. dicchi thick, dense, G. dick thick, Icel.
[thorn]ykkr, [thorn]j["o]kkr, and probably to Gael. & Ir.
tiugh. Cf. Tight.]
1. Measuring in the third dimension other than length and
breadth, or in general dimension other than length; --
said of a solid body; as, a timber seven inches thick.
Were it as thick as is a branched oak. --Chaucer.
My little finger shall be thicker than my father's
loins. --1 Kings xii.
2. Having more depth or extent from one surface to its
opposite than usual; not thin or slender; as, a thick
plank; thick cloth; thick paper; thick neck.
3. Dense; not thin; inspissated; as, thick vapors. Also used
figuratively; as, thick darkness.
Make the gruel thick and slab. --Shak.
4. Not transparent or clear; hence, turbid, muddy, or misty;
as, the water of a river is apt to be thick after a rain.
"In a thick, misty day." --Sir W. Scott.
5. Abundant, close, or crowded in space; closely set;
following in quick succession; frequently recurring.
The people were gathered thick together. --Luke xi.
Black was the forest; thick with beech it stood.
6. Not having due distinction of syllables, or good
articulation; indistinct; as, a thick utterance.
7. Deep; profound; as, thick sleep. [R.] --Shak.
8. Dull; not quick; as, thick of fearing. --Shak.
His dimensions to any thick sight were invincible.
9. Intimate; very friendly; familiar. [Colloq.]
We have been thick ever since. --T. Hughes.
Note: Thick is often used in the formation of compounds, most
of which are self-explaining; as, thick-barred,
thick-bodied, thick-coming, thick-cut, thick-flying,
thick-growing, thick-leaved, thick-lipped,
thick-necked, thick-planted, thick-ribbed,
thick-shelled, thick-woven, and the like.
Thick register. (Phon.) See the Note under Register, n.,
Thick stuff (Naut.), all plank that is more than four
inches thick and less than twelve. --J. Knowles.
Syn: Dense; close; compact; solid; gross; coarse.